CBX3 (human recombinant)

The heterochromatin protein 1 (HP1) family, which consists of isoforms HP1-? (CBX5), HP1-? (CBX1), and HP1-? (CBX3), are chromatin-associated proteins involved in gene regulation and heterochromatin formation.{20846} CBX proteins have an N-terminal chromodomain, a C-terminal chromoshadow domain, and a hinge domain that connects the two.{23468} Extensive post-translational modifications have been observed and mapped on the CBX proteins.{23471} The chromodomain of CBX3 has been shown to recognize methylated histone H3 lysine 9, methylated histone H1 lysine 26, and G9A methylated at lysine 185.{25450} CBX3 associates with the exons of a subset of actively transcribed genes, and loss of CBX3 results in accumulation of unspliced mRNA from that subset of genes.{25452,25453} Further, CBX3 suppresses Nanog gene transcription in pre-induced pluripotent stem cells and long terminal repeat protein expression in HIV-1 infected cells.{25453,25449} Knockdown of CBX3 by siRNA in cells latently infected with HIV-1 leads to virus reactivation.{25448} CBX3 has been proposed to be a biomarker for tumor stem cells in osteosarcoma.{25451}